Free and decomplexed human immunodeficiency virus p24 antigenaemia in black patients with AIDS and AIDS-related disorders.

ABSTRACT

OBJECTIVES: To determine the clinical signification of free and decomplexed p24 antigenaemia in HIV1-infected black individuals. PATIENTS AND METHODS: Sixty African patients with pre-AIDS (n = 12) and AIDS (n = 48), hospitalized in the Centre National Hospitalier Universitaire de Bangui, Central African Republic, were prospectively included. 15 HIV1-seronegative healthy African subjects served as controls. Serum p24 antigenaemia was detected using a polyclonal and a monoclonal sandwich enzyme immunoassay (EIA). All sera were tested again after acid pretreatment (45 mn incubation of serum with a 0.5 N solution of HCl at +37 degrees C). RESULTS: The polyclonal EIA and the monoclonal EIA detected respectively four (7%) to six (10%) free p24 antigen positive samples from the HIV1-infected individuals, with a similar frequency in pre-AIDS and AIDS patients. None of the controls were found p24 antigen positive. After acid pretreatment, the rate of detectable p24 antigenaemia increased significantly, leading with the monoclonal EIA to a 47% positivity rate (p < 0.001), and the patients with AIDS became more frequently p24 antigen positive (54%), than the patients with pre-AIDS (17%) (p = 0.02). CONCLUSION: Detectable p24 antigenaemia in HIV1-infected African subjects could be obtained in nearly half of cases by increasing the sensitivity of the assay using monoclonal EIA and acid hydrolysis of circulating immune complexes. Decomplexed p24 antigenaemia in HIV1-infected Black African patients could have predictive signification similar to free p24 antigenaemia in Caucasians.